【摘要】 在全桥变换器中引入谐振电感和钳位二极管,可以使开关管在较宽的负载范围内实现零电压开关,并且消除输出整流二极管上的电压尖峰。当钳位二极管导通时,谐振电感被短路,电流保持不变,在开关管和钳位二极管中产生较大的导通损耗,而且如果滤波电感较大,钳位二极管有可能无法自然关断,从而产生较大的反向恢复损耗。在全桥变换器中增加一个复位绕组与谐振电感串联,当钳位二极管导通时,利用复位绕组电压使谐振电感电流快速下降,使钳位二极管电流快速减小到零。复位绕组的引入,不仅减小了谐振电感、开关管和钳位二极管的导通损耗,而且使钳位二极管可靠关断,避免了反向恢复。本文详细分析了加复位绕组全桥变换器的工作原理,并讨论变压器绕组匝比的选择,最后进行实验验证,并给出实验结果。更多还原

【Abstract】 Introducing a resonant inductance and two clamping diodes into the full-bridge converter can widen the load range of ZVS and eliminate the voltage oscillation across the rectifier diodes. When the clamping diode conducts, the resonant inductance is short-circuited and its current keeps constant, resulting in large conduction losses in the clamping diode and the power switches. If the output filter inductance is relatively large, the clamping diodes will be hard turned-off and significant reverse recovery loss will occur. In this paper, a reset winding is added to be series with the resonant inductance, which makes the clamping diodes current decay rapidly when the clamping diode is conducting. The reset winding not only reduces the conduction losses, but also makes the clamping diodes naturally turn-off and avoids the reverse recovery. The operation principle of the proposed converter is analyzed. The choice of the turns ratio of transformer is discussed. A 1kW prototype converter is built to verify the operation principle and the experimental results are also demonstrated.更多还原